Sophomoric in the worst possible sense, Richard Kelly’s second feature is nearly two-and-a-half hours of incoherent bluster that’s meant to be as much a satirical take on the post-9/11 world as “Dr. Strangelove” was on the Cold War era, but fails miserably in every respect. I say this with regret, as one who found Kelly’s first film “Donnie Darko” an astonishingly confident debut. But one might have predicted that he was cruising toward a “Heaven’s Gate” debacle when he fashioned his “director’s cut” of “Donnie,” adding so much explication and so many effects that he ruined the hauntingly elliptical quality that made the original picture mesmerizing; sitting through the longer version made one wonder whether its predecessor wasn’t one of those accidental masterpieces that happen along every once in a while as a result of interference that short-circuits a filmmaker’s ability to achieve his full “vision.” Certainly “Southland Tales,” in which Kelly appears to have been given unfettered rein, suggests that he could use some outside help. It’s a complete mess.

I’m referring here to the cut of the film that’s now being released to American theatres with a running-time of 144 minutes, as opposed to the 161 minute version that received a poisonous reaction at Cannes last year. I don’t know what’s been eliminated, but can say it wasn’t enough; or to recast Pauline Kael’s famous remark about Cimino’s original version of “Gate,” I can see what else should have been snipped, but have difficulty identifying anything that should have been retained. There’s barely a frame of “Tales” worth saving.

What’s the movie about? Well, it’s set in an America that’s suffered a nuclear attack (in Texas, of all places) and is suffering from an acute lack of oil. In the climate of paranoia that follows, the government has become crypto-fascist, the Internet has become an officially-run propaganda device, surveillance and defense perimeters are everywhere, the war in the Mideast has expanded, and a group of scientists led by a strangely robed German have developed technology for converting sea waves into energy.

But that’s all just background, against which is set a bewildering array of supposedly colorful characters, who interact in equally bewildering ways. Most notable among them are an action movie star with the unlikely name of Boxer Santaros (Dwayne “The Rock Johnson), who’s married to the daughter of daughter of a senator running for the vice presidency but living with porn star Krysta Now (Sarah Michelle Gellar), with whom he’s written a script called “The Power” in which he’ll play agent Jericho Cane—a pose he periodically adopts in “real” life. Then there are twin brothers Roland and Ronald Tavener (Seann William Scott), one a troubled cop and the other a war veteran. An underground opposition to the existing disorder also exists in the form of various wild-eyed revolutionaries, often with supposedly Marxist connections, that include a left-wing movie-maker (Nora Dunn) and assorted other “Saturday Night Live” castoffs like Cheri Oteri. (Jon Lovitz and Amy Poehler also show up in the course of the cacophony.) Wallace Shawn plays the malevolent German inventor in garb that looks like it was rescued from the wardrobe closet of “Barbarella,” and he’s accompanied by Zelda Rubinstein (from “Poltergeist”) who’s equally strangely clothed. It would be a tedious job to catalogue all the characters who tumble over one another in the course of the picture—they’re played by people as varied as Justin Timberlake (who bursts pointlessly into song at one point, cuing a bad music video episode), Kevin Smith (in a shaggy beard) and Miranda Richardson, looking like something out of a “Star Wars” blooper reel as the would-be vice-president’s wife, who presides over a stealth surveillance operation.

As to what happens, that’s pretty much anyone’s guess, though the big revelation involves Kelly’s “Donnie Darko” hobbyhorse of time travel. All that’s clear is that the viewer has to suffer through a cascade of purportedly clever allusions and wild stylistic exhibitions before arriving at an apocalyptic finale involving a flying truck and a dirigible on which the bigwigs are having a gala July 4 party. That gives Kelly the opportunity to repeat the reversal of T.S. Eliot he’s inserted like a mantra throughout the picture: “This is the way the world ends, not with a whimper but a bang.” Which, it could be said, is the message of “Strangelove” too, except that Kubrick didn’t feel the need to show off his erudition by quoting it and certainly would never have repeated it so often to remind viewers of his juvenile cleverness.

The remainder of the picture’s elements are more like refuse. The acting is terrible, filled with mugging and overbroad exaggeration, the writing puerile and obvious, veering from idiotic non-sequiturs to preachy pronouncements, and even the technical side of things is poor, with the glitzy cuts and swooning camera movements unable to conceal the fact that most of the sets and effects are pretty shabby.

“Southland Tales” isn’t the first film that was roasted at Cannes and released in an attenuated form, of course. One need only recall Vincent Gallo’s “The Brown Bunny,” which was savaged at the festival in 2003 but shown in a shortened version the following year. But the initial reception was correct: it was a terrible movie, and no amount of tinkering could make it less so. But Gallo’s movie was a minimalist fiasco—Kelly’s is a monumental disaster. Maybe the notoriety of “Southland Tales” (and the cult popularity of its maker’s debut film) will attract viewers, and a few will probably claim to find it engaging or profound; but most people unlucky enough to encounter it will recognize it as just an abbreviated but unimproved take on the overweening, harebrained junk the Cannes audience booed. The picture doesn’t have the big rabbit of “Donnie Darko,” or the little stuffed one of Gallo’s, but while it may not feature a brown bunny, it certainly resembles something of the same color with a much more pungent aroma. Let’s just say that the toilet motif that’s notable in the picture seems utterly appropriate.

Gee, maybe “Donnie Darko” wasn’t so good, after all.